1) Field of the Invention
This invention relates generally to rotary drilling apparatus for oil and gas wells and in particular to apparatus for remotely controlling spinning and torquing operations for drill pipe joints or sections of drill pipe joints while going into a hole (connecting joints) or coming out of a hole (disconnecting joints) with rotary table/slip equipment of a drilling rig.
In particular, this invention relates to an assembly of three devices for the drilling rig platform: a remotely controlled powered slip for supporting a drill string in the well, a remotely controlled powered wrench assembly for spinning and torquing operations for coupling or decoupling a drill pipe point to a drill pipe joint which is supported by slips at the rotary table, and a remotely controlled powered manipulator arm for centering or swinging away an additional drill pipe joint or section with or from an existing joint in the powered wrench assembly.
2) Description of the Prior Art
Oil and gas well drilling operations generally employ a string of drill pipe joints or sections with a drill collar and drill bit connected at the bottom end of the string for boring through earth formations while forming a bore hole. The drill string is conventionally rotated by connecting a kelly at the top of the drill string and turning the kelly by a rotary drive located on or beneath the rig floor. Top drive systems are also used. In a rotary table/slip system, the kelly and the drill string transmit the rotary force to the drill bit. One or more drill collars located near the bottom of the drill string provide weight on the bit.
As the bore hole gets deeper, an additional drill pipe section must be added to the string already in the well. To do so, the drill string is lifted by the rig until the top-most drill pipe section extends above the rig floor. Slips are set at the rotary table to prevent the drill string from sinking into the bore hole. The kelly is removed from the upward facing box threads of the top-most drill pipe section. The kelly is then pulled over to a new drill pipe section waiting in a “mouse hole” and has its pin threads made up with the box threads of the new section. Next the kelly and new drill pipe section are moved over and centered into position above the upwardly facing box end of drill string, with a pin end of the new drill pipe section pointing down. The pin of the new section is then stabbed into the upwardly facing box of the drill string. The threaded connection is made up between the box end of the pipe section extending above the rig floor and the pin end of the new pipe section. The box end of the pipe section is gripped by tongs while the pin end is tightly screwed or “spun” into the box. Then additional torque is applied between the pin and box until the threaded connection is properly made up. The drill string with the kelly attached to the top is lowered into the borehole. Drilling continues by turning the kelly with the rotary drive at the top of the drill floor.
Typical drilling operations call for a worker (a “roughneck”) on the rig floor to perform spinning operations with a drill pipe spinner and to perform torquing with tongs on the box and pin upset portions of drill pipe sections to “torque up” or tighten the threaded connection to manufacturer tightness specification. Prior art tongs have included hydraulically powered tongs or manual tongs using wire rope and cathead. Spinners are predominately air or hydraulically powered drill pipe spinning devices. Such tongs and spinners require manual manipulation of the equipment and drill pipe at the drill rig platform floor. Operating the tongs and pipes is inherently dangerous, because a rig employee or “roughneck” must physically handle the powerful equipment near the drill pipe. Accidents have been common with loss of fingers, hands, etc.
When a drill string is being taken out of the bore hole in order to replace a drill bit at the bottom end of the string, a reverse procedure is followed; the threaded connection is loosened or “broke out” with tongs and spun out with a drill pipe spinner.
The prior procedures and equipment described above are inherently dangerous to roughnecks working to make-up and break apart and disconnect drill pipe connections. Not only is the roughneck beneath the drill pipe section as it swings from the side of the hole for make up or disconnection operations, he must also handle the slips, the spinner and the tongs many times when the string is being made up while reentering the well or removing the string from the well.
Powered equipment such as power tongs and spinners have been provided with limited remote control in a tool called the “Iron Roughneck”. One description of an Iron Roughneck machine is provided in U.S. Pat. No. 4,348,920. That patent shows a power driven tool for making and breaking threaded connections in a well pipe that is moveable between a central position of alignment with the well axis and a retracted or inactive position offset at a side of the well axis. The Iron Roughneck tool of the '920 patent includes a carriage which rolls horizontally from the side of the well axis between inactive and active positions on spaced tracks. A pipe contacting mechanism is arranged to move up and down with respect to the carriage and includes an upper well pipe spinner and a lower torque wrench assembly. The Iron Roughneck of the '920 patent includes an arrangement which provides pivotable movement to an inclined position for alignment of the kelly with a new drill pipe section in a mousehole.
The Iron Roughneck has solved some of the safety problems of manual tongs and spinners, yet problems still exist. The first is that horizontal movement on the rig floor takes up limited horizontal space. Furthermore, manual centering of a new pipe joint with a pipe joint in the well may be required. Manual placing of slips in the rotary table to support the drill string in the well may also be required. All such manual operations at the well center create the opportunity for accidents to well operating personnel.
3) Identification of Objects of the Invention
A primary object of the invention is to provide an assembly of remotely controlled equipment for operations at the rig floor when adding or removing tool joints to or from a drill string or including a remotely controlled powered slips tool, a remotely controlled tool joint connecting and disconnecting tool, and a remotely controlled manipulator arm for centering an additional tool joint with an existing tool joint in the drill string.
Another object of the invention is to provide a remotely controlled tool joint connecting and disconnecting tool which requires no horizontal movement along the drilling platform floor for saving valuable space on the platform floor.
Another object of the invention is to provide a remotely controlled hydraulically powered drill pipe connecting and disconnecting tool which is installed without being horizontally moveable with respect to the well axis and requires no manual manipulation of equipment at the well enter when tool joints are being connected or disconnected.